Add an example of onresponse hooks

Also fix the guide entry on hooks.

1 files changed, 21 insertions, 0 deletions

diff --git a/examples/error_hook/src/error_hook_responder.erl b/examples/error_hook/src/error_hook_responder.erl
new file mode 100644
index 0000000..31f2d5b
--- /dev/null
+++ b/examples/error_hook/src/error_hook_responder.erl
@@ -0,0 +1,21 @@
+%% Feel free to use, reuse and abuse the code in this file.
+
+-module(error_hook_responder).
+
+-export([respond/4]).
+
+respond(404, Headers, <<>>, Req) ->
+	{Path, Req2} = cowboy_req:path(Req),
+	Body = <<"404 Not Found: \"", Path/binary, "\" is not the path you are looking for.\n">>,
+	Headers2 = lists:keyreplace(<<"content-length">>, 1, Headers,
+		{<<"content-length">>, integer_to_list(byte_size(Body))}),
+	{ok, Req3} = cowboy_req:reply(404, Headers2, Body, Req2),
+	Req3;
+respond(Code, Headers, <<>>, Req) when is_integer(Code), Code >= 400 ->
+	Body = ["HTTP Error ", integer_to_list(Code), $\n],
+	Headers2 = lists:keyreplace(<<"content-length">>, 1, Headers,
+		{<<"content-length">>, integer_to_list(iolist_size(Body))}),
+	{ok, Req2} = cowboy_req:reply(Code, Headers2, Body, Req),
+	Req2;
+respond(_Code, _Headers, _Body, Req) ->
+	Req.